cavernous hemangioma-a raised, red or purple mark in the skin, made up of enlarged blood vessels.

cellulitis-a bacterial infection of the skin that is characterized by swelling and tenderness.

chemical peels-a procedure often used to minimize sun-damaged skin, irregular pigment, and superficial scars. The top layer of skin is removed with a chemical application to the skin. By removing the top layer, the skin regenerates, often improving the skin's appearance.

cold sore-small blisters around and in the mouth caused by the herpes simplex virus.

collagen-a natural protein found in humans that forms connective tissue and provides strength, resilience, and support to the skin, ligaments, tendons, bones, and other parts of the body.

collagen injections-one type of collagen, which is derived from purified bovine (cow) collagen, is injected beneath the skin to replace the body's natural collagen that has been lost. Injectable collagen is generally used to treat wrinkles, scars, and facial lines.

creeping eruption-a skin infection caused by hookworms that is characterized by severe itching.

crust (Also called scab.)-a formation of dried blood, pus, or other skin fluid over a break in the skin.

cryosurgery-destruction of a lesion on the skin by freezing with liquid nitrogen.

dermabrasion-used to minimize small scars, minor skin surface irregularities, surgical scars, and acne scars. As the name implies, dermabrasion involves removing the top layers of skin with an electrical machine that "abrades" the skin. As the skin heals from the procedure, the surface appears smoother and fresher.

dermatitis-a number of skin conditions characterized by inflammation of the skin.

dermatofibroma-small, red or brown bumps in the skin.

dermis-the middle layer of skin, which is made up of blood vessels, lymph vessels, hair follicles, sweat glands, collagen bundles, and fibroblasts.

dermoid cyst-a benign tumor made up of hairs, sweat glands, and sebaceous glands.

macular stains (Also called angel's kisses or stork bites.)-faint, red marks that appear in the skin at birth. Angel's kisses are marks on the forehead and eyelids. Stork bites are marks on the back of the neck.

macule-the smaller version of a patch - a flat discolored spot.

malignant melanoma-a rare, but sometimes deadly, skin cancer that begins as a mole that turns cancerous.

melanocytes-cells present in the epidermis that produce melanin (skin pigment).

melasma-dark, brown symmetrical patches of pigment on the face.

moles-small skin marks caused by pigment-producing cells in the skin.

Mongolian spots-Bluish-black marks on the lower back and buttocks; affects mainly African-American or Asian children.

punch grafts-small skin grafts to replace scarred skin. A hole is punched in the skin to remove the scar, which is then replaced with unscarred skin (often from the back of the earlobe). Punch grafts can help treat deep acne scars.

pustule (Also called pimple.)-inflamed lesions that look like pink bumps.